UCC28600-Q1: Does our device support Single current closed loop control?

Sherry Liang

Part Number: UCC28600-Q1
Other Parts Discussed in Thread: UCC28740, UCC28600

Dear team,

My customer uses our device in below architecture to replace UCC28740, but now they encounter one problem. When they are doing current closed-loop control, there will be oscillations. We saw the description in one document 'When the duty cycle of the current mode control converter exceeds 50%, the converter will oscillate at the sub-harmonic frequency of the switching frequency''. We are not sure whether this is the root cause. If it is, do we have any method to avoid the oscillation? Can we limit the duty cycle below 50%? Does our device support Single current closed loop control?

PMP21959RevA_Sch_20190402.pdf

Thanks & Best Regards,

Sherry

over 4 years ago

0 Mike O' over 4 years ago

TI__Guru* 86206 points

Hello,

Not sure why your customer wants to replace the UCC28740 with the UCC28600. The UCC28740 is valley switched and easier to design with compared to the UCC28740.

The UCC28600 can be designed for peak current mode and was designed for true quasi resonant operation. If you are just trying to change from the UCC28740 to the UCC28600 you may have to redesign the transformer that is being used in the design; as well as, loop compensation components.

There is a Webench design tool or excel design tool that you can use to check the transformer turns ratio; as well as, as the compensation comments used in your design based on your input and output power requirements. You can fine these tools at the following web link.

https://www.ti.com/product/UCC28600?keyMatch=UCC28600&tisearch=search-everything&usecase=GPN#design-development##design-tools-simulation

Regards,

Mike

Power management

Power management forum

UCC28600-Q1: Does our device support Single current closed loop control?